Wafer handling end effector

Abstract

An end effector for supporting a wafer is disclosed. The end effector comprises a main body, a vacuum line formed in the main body, a first support arranged for contacting an inner area of a wafer, at least one opening within a boundary of the first support in communication with the vacuum line, and at least one second support arranged for contacting an outer edge of a wafer.

1 . An end effector for supporting a wafer comprising a main body, a vacuum line formed in the main body, a first support arranged for contacting an inner area of a wafer, at least one opening within a boundary of the first support in communication with the vacuum line, and at least one second support arranged for contacting an outer edge of a wafer. 
     
     
         2 . An end effector according to  claim 1 , wherein the first support arranged for contacting an inner area of a wafer comprises a central raised area and at least one circular raised area arranged concentric with the central raised area such that when a wafer is supported on the first support, an enclosed volume is formed between the wafer and the first support. 
     
     
         3 . An end effector according to  claim 1 , wherein the first support arranged for contacting an inner area of a wafer comprises a central raised area and at least two circular raised areas arranged concentric with the central raised area such that when a wafer is supported on the first support, an enclosed volume is formed between the wafer and the first support. 
     
     
         4 . An end effector according to  claim 2 , wherein the vacuum line is in communication with the enclosed volume. 
     
     
         5 . An end effector according to  claim 3 , comprising a first vacuum line in communication with a first enclosed volume between the central raised area and an adjacent concentric circular raised area, and a second vacuum line in communication with a second enclosed volume between two concentric circular raised areas. 
     
     
         6 . An end effector according to  claim 1 , wherein a height of the at least one second support is less than a height of the first support. 
     
     
         7 . An end effector according to  claim 1 , wherein the main body has a fork shape with a main part and two projecting parts, wherein the at least one second support comprises respective second support parts on the two projecting parts and a second support part on the main part. 
     
     
         8 . An end effector according to  claim 1 , wherein the at least one second support is generally arc shaped. 
     
     
         9 . An end effector according to  claim 1  wherein the at least one second support is circular. 
     
     
         10 . An end effector according to  claim 1 , wherein the at least one second support projects from a plane of the end effector while having an angle with the plane of the end effector which is between 1 and 90 degrees. 
     
     
         11 . An end effector according to  claim 1 , comprising at least two second supports arranged for contacting an outer edge of a wafer, wherein each of the at least two second supports comprises a respective piezoelectric actuator configured to cause the respective second support to move between a wafer gripping position and a wafer release position. 
     
     
         12 . An end effector according to  claim 11 , wherein when in a wafer gripping position, a second support is closer to the first support than when in a wafer release position. 
     
     
         13 . An end effector according to  claim 11 , wherein when in a wafer gripping position, a second support is further away from the first support than when in a wafer release position. 
     
     
         14 . An end effector according to  claim 11 , wherein when in a wafer gripping position, a second support has the same distance from the first support as when in a wafer release position. 
     
     
         15 . An end effector according to  claim 11 , wherein the main body has a fork shape with a main part and two projecting parts, wherein at least one second support comprising a piezoelectric actuator is disposed on one projecting part, and at least one second support comprising a piezoelectric actuator is disposed on the other projecting part. 
     
     
         16 . A wafer handling apparatus comprising a wafer handling robot, an end effector according to  claim 11 , a vacuum pump connected to the vacuum line of the end effector, and a control module configured to receive a wafer type of a wafer to be handled by the wafer handling apparatus and to set the vacuum pump to an on status or an off status depending on the wafer type. 
     
     
         17 . A wafer handling apparatus according to  claim 16 , wherein the control module is additionally configured to control a gripping status of the piezoelectric actuator depending on the wafer type.